Artificial ankle joint



Dec. 12, 1939. w. F. KAISER ARTIFICIAL ANKLE JOINT Filed Sept. 16, 1958 BY 'h/mv/ A TORNEY.

Patented Dec. 12, 1939 v units it ARTIFICEAL ANKLE JOINT William'F. Kaiser, Youngstown, Ohio, assignor to Joseph Spievak, Youngstown, Ohio Application September 16, 1938,'Serial No. 230,263

3 Claims.

This invention relates to an artificial foot and more particularly to the ankle joint therein. The principal object of this-invention is the provision of an improved ankle joint structure.

A further object of this invention is the provision of an improved ankle joint structure so formed that the entire weight on the artificial foot-is supported upon a rubber cushion at all times. I

A still further object of this invention is the provision of an improved artificial foot, the various parts of which may be conveniently detached from one another and the various rubber portions thereof conveniently replaced when worn.

The artificial foot shown and described herein has been designed primarily to insure comfort to the-wearer. In order to eliminate all shock normally transmitted to the stump of the wearer the entire mechanical action of the ankle joint in the artificial foot has been positioned upon a thick rubber cushion in such manner that the entire Weight upon the. foot is carried directly upon the rubber cushion, this results in increased comfort to'the wearer and substantially longer life to the foot itself, as all the pull or jerk upon the joint structure is eliminated.

The provision of the rubber cushion mounting of the ankle joint also results in an improved lateral motion which in turn helps retain the stump of the wearer in proper fitting position in the socket of the artificial limb, the yielding action of the ankle joint thus tending to eliminate chafing and bruising and jarring on the stump.

With the foregoing and other objects in View which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed, without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawing, wherein:

Figure 1 is a cross sectional view of the artificial foot showing the ankle joint thereof, in

' detail.

Figurez is a top plan view of the lower portion of the artificial foot, the top or shank portion thereof having been removed. Lines l-l on this figure indicate the cross section shown in Figure 1.

Figure 3 is a side elevation with parts broken relationto the foot I.

away showing a portion of the artificial foot adjacent to'the ankle joint thereof.

By referring to the drawing and Figures 1 and 2 in particular it will be seen that the invention comprises an artificial foot having an improved ankle joint construction.

The foot I being connected to the top or shank 2 by means of a swing bolt assembly comprising a bolt 3 the upper end 4 of which is threaded and adapted to receive a-flanged nut 5 which isin 1 turn positioned upon the end of the threaded bolt twithin a recess 6 in the shank 2.

The lower end of this threaded bolt 3 is formed into aipair of arms I, each of these arms I being provided with an opening adapted to receive a =15 tubular bearing 8; Positioned on this tubular bearing 8 and between the arms of the boltt there is a bearing block 9 which is provided at its sides with secondary tubular bearings l0. Positioned on each of these secondary bearings 20 Hi there are bolts j H which have circular openings formed in their upper ends thus adapting them to be positioned upon the secondary tubular bearings Ii! in such manner that they will pivot thereon.

In order that the swing bolt assembly may be positioned within the foot and yet not rest directly upon it a rubber cushion [2 has been provided and is so placed Within a recess in the foot l that the entire swing bolt assembly rests upon it. The bolts l l extending downwardly through openings in the foot I, and at their lower ends are threaded and provided with circular nuts It. In order to hold these threaded nuts IS in proper position a wire it may be threaded through openings therein and in effect key these circular nuts I3 in position. This is necessary because the swing bolt assembly resting upon a rubber cushion as it does will move in 40 It will be seen that the swing bolt assembly will provide universal action closely approximating that of a human ankle joint. In order to control the progressive and lateral action further use is made of rubber and particularly of a sponge rubber section I5 of the foot I.

Centrally positioned in the heel of the. foot l and extending through the sponge rubber section it there is a rubber block it which is adapted to extend upwardly into a recess H in the shank '2. This rubber block l6 helps keep the foot in correct position in relation to the shank 2 and provides a limit to the progressive motion permitted by the ankle joint. A rubber pad I8 is positioned in another recess [9 at the instep of the foot I and is adapted to limit the movement of the shank 2 in relation thereto.

It will be seen that I have provided an improved ankle joint structure in an artificial foot, 5 designed to provide a controlled lateral action as well as a controlled progressive action. The entire mechanical structure of the ankle joint and foot being cushioned directly upon yielding rubber in such manner that it is impossible for shock to reach the wearer through the foot.

What I claim is: 1. In an artificial limb comprising a foot and a leg portion; an ankle joint connecting the said foot and leg portions together, the said ankle joint comprising a vertical bolt, the upper end of which is adapted to be attached to the said leg portion, and having a pair of arms formed on the lower end thereof, openings formed in the said arms, a tubular bearing positioned in the said openings, a bearing block positioned on the said tubular bearing between the said arms, secondary tubular bearings formed at the sides of the said bearing block, bolts with openings formed in their upper ends positioned on the said 26 secondary tubular bearings, the said bolts adapted to be attached to the said foot portion, a rubber cushion crescent shaped in cross section, transversely positioned between the said swing bolt assembly, its tubular bearing and the said 30 foot, so that shock from the ground contact will not reach the wearer and will provide a controlled lateral action in the said ankle joint.

2. An artificial limb comprising a foot and a shank portion, an ankle joint connecting the said 35 foot and shank portions together, the said ankle joint being carried entirely upon a rubber cushion, and comprising a vertical bolt attached to the said shank portion, the lower end of the said vertical bolt being formed into a pair of arms having openings therein, a tubular bearing positioned through the said openings, 2. bearing block positioned upon the said tubular bearing between the said arms, the said tubular bearing and bearing block adapted to rest upon the said rubber cushion in such manner that lateral action of the ankle joint will cause the tubular bearing to compress the rubber cushion, secondary tubular bearings formed on the sides of the said bearing block and adapted to receive a pair of bolts having openings formed in their upper ends, the said bolts adapted to be attached to the said foot yieldingly so that shock will be absorbed by the said rubber cushion and not transmitted to the wearer.

3. An artificial limb, an ankle joint comprising a foot member, a pad of rubber occupying the axis of the ankle joint and extending transversely across the same; a swing bolt assembly positioned on the said pad of rubber; the said swing bolt assembly comprising a vertical bolt attached to the said shank portion; the lower end of the said vertical bolt being formed into a pair of arms having openings therein; a tubular bearing positioned between the said openings; a bearing block positioned upon the said tubular bearing between the said arms; secondary tubular bearings formed on the sides of the said bearing block and adapted to receive a pair of bolts having openings formed in their upper ends; the said bolts adapted to be attached to the said foot yieldingly; the entire mechanical assembly being positioned on the said pad of rubber so that shock will be absorbed thereby.

WILLIAM F. KAISER. 

